You're missing more than just sound. You're missing the chipset drivers, the audio driver, video card driver and who knows what possibly else. Biggest problem is you have a 7-8 year old motherboard,
that has zero Windows 7 support, and at best will have to make do with either XP or possibly Vista drivers (if available) to get things working properly. Let's start with the chipset drivers as without that nothing else really matters. That motherboard from the Speccy screen shot has the old Via KT600 chipset on it and for that there is a Vista driver available. Don't normally post direct download links but it is easier than explain how to find them. Start with downloading and installing this,
to get it to install. Next need to find out whether it is Realtek audio or Via audio. Open Device Manager, right click on the sound card and select Properties, then click on the Details tab and select Hardware IDs from the dropdown and post back a screen shot of what it shows.